Nov 17 (Reuters) - Wall Street’s main indexes were on track to post small weekly losses on Friday as investors were skeptical about the Republicans’ efforts to pass the tax bill.

The House of Representatives took important steps on Thursday toward the biggest U.S. tax-code overhaul since the 1980s, approving a broad package of cuts, while a Senate panel advanced its own version of the legislation.

Tax debate shifts to the Senate, where the plan has already faced resistance and the Republican majority is much slimmer.

“The market is still kind of nervous with respect to the tax bill moving to the next stage,” said Massud Ghaussy, director at Nasdaq Advisory Services.

“The GOP can afford only two defections and they are not expecting any Democrats to vote for it.”

At 10:56 a.m. ET (1456 GMT), the Dow Jones Industrial Average was down 75.47 points, or 0.32 percent, at 23,382.89, the S&P 500 was down 3.51 points, or 0.14 percent, at 2,582.13 and the Nasdaq Composite was down 2.73 points, or 0.04 percent, at 6,790.56.

Strong earnings and good economic data have underpinned much of the rally this year. The S&P 500 has risen about 15 percent this year, its biggest gain in four years.

“We’ve been seeing a decent run-up in stocks recently, and it’s just wobbly couple of days.”

Oil prices rose but remained on course for their first week of losses in six, as concerns grew over Russia’s support for an extension of the crude output cuts that have bolstered prices in recent months.

Shares of Twenty-First Century Fox rose 4 percent after sources said Comcast and Verizon had expressed interest in acquiring a significant part of the company’s assets.

Those, along with a surge for sports retailers including Foot Locker, Shoe Carnival and Hibbett Sports were the latest signs of a revival of fortunes in a battered U.S. retail sector.

But adding to pressure on the dollar was a Wall Street Journal report that investigators probing possible Russian interference in the 2016 U.S. election had subpoenaed President Trump’s election campaign for documents.

A surprise launch of a $200,000 sports car by Tesla, helped its shares rise about 3 percent.

Advancing issues outnumbered decliners on the NYSE by 1,552 to 1,175. On the Nasdaq, 1,426 issues fell and 1,295 advanced. (Reporting by Sruthi Shankar in Bengaluru; Editing by Anil D‘Silva)